Study Says Moderate Marijuana Smoking Doesn’t Hurt Lungs

Posted on Jan 11, 2012

Now, before you rush out and follow Snoop Dogg’s lead, you might read the fine print about a new NIH-funded study about moderate long-term marijuana use and its effects (or lack thereof) on lung function. On the other hand, the study makes a strong case for giving up cigarettes and rolling a joint.

This significant new study suggests that pot enthusiasts who enjoy a joint a day may not encounter the kinds of health issues that habitual cigarette smokers, or those who mix their weed with tobacco, risk after years of use. Heavier indulgence may pose problems, but the take-away here is that the smoke signals we’ve been getting about marijuana might have been misleadingly negative, and we’re not just talking about “Reefer Madness” here. —KA

The New York Times:

The new research is one of the most extensive looks to date at whether long-term marijuana use causes pulmonary damage, and specifically whether its impact on the lungs is as harmful as smoking cigarettes. The researchers followed more than 5,000 people over two decades and found that regularly smoking marijuana — the equivalent of up to a joint a day over seven years — did not impair performance on a lung function test. The test, a measure of pulmonary obstruction that looks at the amount of air a person can force out in one second after taking a deep breath, is typically worsened by smoking tobacco.

[...] The researchers found that for marijuana smokers, an exposure of up to seven “joint years” — with one joint-year equivalent to smoking 365 joints or filled pipes, or an average of one joint a day for seven years — did not worsen pulmonary function. Dr. Kertesz noted that with heavier marijuana use, described as 10 joint-years of exposure or more, lung function did begin to decline. And for a person who smokes both marijuana and cigarettes, “the net effect is going to be continued loss of lung function.”